A conventional track-type vehicle, such as a tractor, is mounted on a pair of endless track assemblies which include a plurality of pivotally interconnected track shoes. The track shoes are pivotally connected together by a link assembly disposed intermediate the width of the shoes and which includes pairs of laterally spaced links pivotally interconnected by pin and bushing assemblies. Upon operation of the vehicle the track shoes are subjected to severe torsional loads, particularly when relatively wide low ground pressure (LGP) track shoes are employed and the vehicles traverses uneven terrain wherein the track shoes engage rocks, stumps and the like. Such loading of the track shoes tends to bend them as well as to impose shear loads on the bolts which secure the track shoes to the link assembly.
Furthermore, such torsional loads are transmitted to the pin and bushing assemblies which tends to wallow-out the bushing bores and to cause pin drift. Should the forces imposed on the pin and bushing assemblies become too severe, the links may also be subjected to damage, such as cracking. Similar problems also arise with pin and bushing assemblies of the sealed and lubricated type wherein extraneous forces imposed thereon subject the assemblies to loss of lubricant. A related problem is one of track shoe interference whereby an end of one track shoe will deflect into engagement with an end of an adjacent track shoe to cause metal-to-metal contact therebetween to cause wear thereof.
Although the above problems are not readily apparent with respect to conventional track assemblies, having track shoes with relatively small widths, such problems become pronounced when a standard track shoe is substantially widened. The widened track shoe (LGP or low ground pressure track shoe) has found particular application when the vehicle is working over swampy or marshy ground conditions, such as during a logging operation. The floatation, traction and related operational characteristics of the vehicle are greatly aided with the use of the wider track shoes. However, the widened track shoes aggravate the above-mentioned problems since the cantilevered ends thereof, outboard of the link assembly, create substantial moments when forces are applied to the ends of the track shoes, such as when the track shoes engage a rock, tree stump, or the like. It should be further understood that since the outboard ends of the track shoes are disconnected from each other the reaction forces imposed on one track shoe will not be fully shared by the other track shoes.
Although the basic problem of transmitting high torsional loads to the track shoes and link assembly may be somewhat alleviated by "beefing-up" the component parts thereof, it should be obvious to those skilled in the arts relating hereto that such an approach has many economical and operating disadvantages, including those resulting from the substantial weight that must be added to the track assembly.